Process for preparing polyester alcohols and use thereof for preparation of polyurethanes

Abstract

The invention relates to a process for preparing polyester alcohols by catalytically reacting at least one at least difunctional carboxylic acid or a derivative thereof with at least one at least difunctional alcohol, which comprises performing at least part of the reaction in the presence of microwave radiation.

1 ) A process for preparing polyester alcohols by catalytically reacting at least one at least difunctional carboxylic acid or a derivative thereof with at least one at least difunctional alcohol, which comprises performing at least part of the reaction in the presence of microwave radiation. 
     
     
         2 ) The process according to  claim 1 , wherein the catalytic reaction is performed in two stages and comprises the following process steps:
 2a) preparing at least one base polyester alcohol by the reaction of in each case at least one at least difunctional carboxylic acid or derivative thereof with in each case at least one polyhydroxyl compound,   2b) reacting the product from step a) or a mixture of the product from step a), optionally in a mixture with at least one further polyhydroxyl compound, in the presence of microwave radiation.   
     
     
         3 ) The process according to  claim 2 , wherein the base polyester alcohol preparable in step 2a) has a molecular weight of more than 1000 g/mol. 
     
     
         4 ) The process according to  claim 2  or  3 , wherein step a) is performed in the presence of microwave radiation. 
     
     
         5 ) The process according to  claim 2  or  3 , wherein step b) is performed in the presence of microwave radiation. 
     
     
         6 ) The process according to  claim 1 ,  2  or  3 , wherein the entire reaction is performed in the presence of microwave radiation. 
     
     
         7 ) The process according to any of  claims 2  to  6 , wherein step b) is performed continuously. 
     
     
         8 ) The process according to any of the preceding claims, wherein the at least difunctional carboxylic acid or the derivative thereof is selected from the group comprising adipic acid, succinic acid, glutaric acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalenedicarboxylic acids, and comprising the derivatives of the carboxylic acids mentioned, especially carboxylic esters and carboxylic anhydrides. 
     
     
         9 ) The process according to any of the preceding claims, wherein the at least difunctional alcohol is selected from the group comprising di- and trifunctional alcohols, preferably having 2 to 12 carbon atoms, more preferably from the group comprising ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerol and trimethylolpropane. 
     
     
         10 ) The process according to any of the preceding claims, wherein the catalyst is selected from the group of the esterification catalysts comprising toluenesulfonic acids and organometallic compounds. 
     
     
         11 ) The process according to any of  claims 2  to  10 , wherein the at least one further polyhydroxyl compound is selected from the group of the at least difunctional alcohols as described in  claim 9 . 
     
     
         12 ) The process according to any of the preceding claims, wherein the energy input of the microwave radiation is at least 5% and at most 95% of the total energy required. 
     
     
         13 ) The use of microwave radiation in a process for preparing polyester alcohols. 
     
     
         14 ) Polyesterol alcohols preparable according to any of  claims 1  to  12 . 
     
     
         15 ) The use of polyester alcohols according to  claim 14  for preparation of polyurethanes.